title: The prevention of ferric nitrilotriacetate-induced nephro- and hepatotoxicity by methylenedioxybenzene antioxidants.
abstract: Previously it was shown that methylenedioxybenzenes (MDBs), particularly isosafrole, were highly effective at preventing CCl4-induced liver necrosis in vivo (Z.S. Zhao, P.J. O'Brien, The prevention of CCl4-induced liver necrosis in mice by naturally occurring methylenedioxybenzenes, Toxicol. Appl. Pharmacol., 140 (1996) 411-421), probably as a result of forming metabolic intermediate complexes with cytochrome P450. In the following it was shown that pretreatment of mice with isosafrole also completely prevented ferric nitrilotriacetate (FeNTA)-induced renal necrosis and lipid peroxidation, even though metabolic activation by cytochrome P450 is not involved. The naturally occurring or synthetic MDBs that prevented CCl4 hepatotoxicity also prevented hepatocyte lipid peroxidation. induced by FeNTA, but other cytochrome P450 inhibitors were ineffective. These compounds, in decreasing order of antioxidant effectiveness, were sesamol, 4-t-butyl-methylenedioxybenzene, isosafrole, piperonyl butoxide and 4-bromo-methylenedioxybenzene and safrole, whereas, benzodioxole, 3,4-(methylenedioxy)-toluene and 1,2-(methylenedioxy)-4-nitrobenzene were ineffective. Pre-incubating the hepatocytes with P450 inhibitors decreased the protective effects of isosafrole, suggesting that the catecholic metabolites of MDBs were responsible for the antioxidant activity. A greater inhibition of FeNTA-induced lipid peroxidation by catecholic metabolites was observed. Since cytochrome P450 did not participate in FeNTA-induced hepatocyte or microsomal lipid peroxidation, it is likely that the antioxidant properties of MDBs or their catecholic metabolites also contribute to their in vivo protection against CCl4 or FeNTA-induced hepato- or nephrotoxicity.
authors.affiliation: Faculty of Pharmacy, University of Toronto, Ont., Canada.
authors.forename: Z S
authors.initials: ZS
authors.lastname: Zhao
authors.forename: S
authors.initials: S
authors.lastname: Khan
authors.forename: P J
authors.initials: PJ
authors.lastname: O'Brien
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002273:Carcinogens / Q000633:toxicity; D056486:Chemical and Drug Induced Liver Injury; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004149:Dioxoles / Q000494:pharmacology*; D005290:Ferric Compounds / Q000633:toxicity; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology; D007674:Kidney Diseases / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008107:Liver Diseases / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D009336:Necrosis; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012451:Safrole / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D002273:Carcinogens; D004149:Dioxoles; D005290:Ferric Compounds; D003577:Cytochrome P-450 Enzyme System; C040539:1,3-benzodioxole; D009571:Nitrilotriacetic Acid; D012451:Safrole; C015959:isosafrole; C020326:ferric nitrilotriacetate